JP2013099206A - Single phase brushless motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single phase brushless motor controller including an overvoltage protective circuit that prevents withstand voltage breakdown of a driving circuit, a power supply circuit or the like, without requiring any additional component even in a motor comprised of a single phase coil.SOLUTION: A single phase brushless motor controller includes: a driver circuit 11 to drive a motor coil 13; a pre-driver 10 to generate control signals of driver circuit switching elements M11-M14 constituting the driver circuit 11 on the basis of a signal that has detected the position of a rotor and an output of the driver circuit 11; an overvoltage detection circuit 12 to form a regeneration route when a potential of the output of the driver circuit 11 increases, from a power supply voltage, up to a potential not less than a threshold value that is preset; and a regeneration route switching element constituting the regeneration route.

Description

  The present invention relates to overvoltage protection of a single-phase brushless motor drive circuit, and in particular, by securing a regenerative current path when switching the energization direction, the overcurrent protection is avoided by preventing the regenerative current from flowing back to the power supply circuit. It is something that can be done.

The drive circuit of the brushless motor is generally configured as shown in FIG. The drive circuit includes an output driver 51 that drives the motor coil 53 and a pre-driver 50 that generates a control signal based on rotor position detection signals S50 to S52 represented by the output of the Hall element. The output driver 51 includes MOS transistors M51 to M54.
In addition, as shown in FIG. 8, the output state of each node in the case of the configuration of FIG. 7 is based on the rotor position detection signals S50 to S52, and the control signals P51 to P53 and N51 to N53 of the MOS transistors M51 to M54 are generated. As is well known, these control signals change the U, V, and W phase signals of the motor coil 53.

In the following drawings, for convenience of explanation, the potentials of the terminals U, V, and W are expressed using the same symbols U, V, and W.
A case where PWM (Pulse-Width-Modulation) control as shown in FIG. 9 is performed in the general drive circuit described above will be described.
When the MOS transistor M51, M53, M55 by the PWM control is in the OFF period, if any of the MOS transistors M52, M54, M56 that have been turned off is turned off, the coil current regeneration path is cut off. As shown in the figure, the potentials at the terminals U, V, and W of the motor coil 53 are rapidly increased to be in an overvoltage state. This overvoltage state may cause breakdown of the drive circuit, the power supply circuit, and the like.

In FIG. 9, the regeneration path is cut off at times T5, T7, T9, and T11, and an overvoltage state is established between times T5 to T6, T7 to T8, T9 to T10, and T11 to T12.
As a countermeasure against this, a general method is to protect against overvoltage by adding a capacitor or a Zener diode having a large capacity between the power supplies. However, this measure has a drawback associated with an increase in cost. In the case of a small motor, the mounting area may not be secured.

There has been proposed a method capable of implementing the above-described overvoltage protection without using a capacitor having a large capacity, a Zener diode, or the like (see, for example, Patent Document 1).
Whenever the path of the regenerative current is interrupted, one of any two terminals U, V, and W of the motor coil 53 is at a potential equal to or higher than the power supply voltage (VDD) and the other is equal to or lower than the ground level (GND). (State X).

As shown in FIGS. 10 and 11, a conventional overvoltage detection circuit 52 that does not use a capacitor having a large capacity, a Zener diode, or the like will be described.
In this circuit, the state X is detected by the overvoltage detection circuit 52, the low-side MOS transistors (M52, M54, M56) that have risen above the power supply voltage, and the high level that has fallen below the ground level or below a predetermined level with respect to the ground level. The side MOS transistors (M51, M53, M55) are forcibly turned on.

  As a result, a regenerative path that has been cut off is formed, and an increase in the coil terminal potential is suppressed. The operation shown in FIG. 11 is an output state of each node when the low-side MOS transistor is forcibly turned on.

JP 2003-47255 A

However, the above-described overvoltage detection circuit that does not use a large-capacitance capacitor, Zener diode, or the like has the following problems.
In other words, the conventional technology can be applied to the motor constituted by the three-phase or plural-phase motor coils as described above, but cannot detect the overvoltage in the case of the motor constituted by the single-phase coil. In some cases, the regenerative current path is cut off, resulting in an overvoltage state.

Further, in the case of a motor composed of a single-phase coil, the regenerative current path is interrupted when switching the energization direction of the coil current regardless of the presence or absence of PWM control, so that overvoltage protection is often required.
A configuration example in the case where a conventional technique is applied to a motor drive circuit constituted by a single-phase coil will be described with reference to FIG. FIG. 13 shows the output state of each node at this time, and FIG. 14 shows a general configuration example of the pre-driver 120 in FIG.

The pre-driver 120 shown in FIG. 14 generates dead time between the rotor position detection signal S10 and the signal inverted by the inverter 31 by the dead time generation circuits 32 and 33, and outputs the output signals S11 to 14 to the buffers 34 to 37. The control signals P11, N11, P12, and N12 are generated via
As shown in FIG. 13, when the energization direction is switched from the output terminal OUT2 to the output terminal OUT1 at the time T1 from the energization state of the coil current from the output terminal OUT1 to the output terminal OUT2 in FIG. The path of the regenerative current is cut off, and the potential of the output terminal OUT2 rises.

At this time, the overvoltage detection circuit 122 detects that the potential of the output terminal OUT2 has risen to the power supply voltage or higher, and forcibly controls the MOS transistor M124 to form a regeneration path. The rise can be suppressed.
However, in the case of the configuration of the general pre-driver 120 shown in FIG. 14, at the time T2 after the time Tdead (see FIG. 13) set by the dead time generating circuits 32 and 33 has elapsed from the energization direction switching start time T1. The OUT2 side high-side MOS transistor M13 is ON-controlled.

For this reason, the output terminal OUT2 and the power supply are brought to substantially the same potential by being short-circuited through the MOS transistor M13.
Therefore, the overvoltage detection circuit 122 cannot detect the overvoltage state of the output terminal OUT2, and the potentials of the output terminal OUT2 and the power supply are in an overvoltage state from time T2 to T3, so that the drive circuit, the power supply circuit, etc. There is a possibility of destroying.

  Therefore, an object of the present invention is to eliminate the need for additional parts such as a capacitor having a large capacity and a Zener diode even in a motor constituted by a single-phase coil, and by forming a regeneration path, a withstand voltage of a drive circuit, a power supply circuit, etc. An object of the present invention is to provide a single-phase brushless motor control device including an overvoltage protection circuit that prevents breakdown.

In order to achieve the above object, the single-phase brushless motor control device of the present invention is configured as follows.
A single-phase brushless motor control device according to the present invention is a single-phase brushless motor control device that controls the direction in which a motor coil is energized based on a signal that detects the position of a rotating rotor, and a driver that drives the motor coil A pre-driver that generates a control signal for a switching element for a driver circuit constituting the driver circuit based on a circuit, a signal for detecting the position of the rotor, and an output of the driver circuit; and an output of the driver circuit When the potential rises from a power supply voltage to a potential equal to or higher than a preset threshold value, an overvoltage detection circuit that forms a regeneration path and a regeneration path switching element that forms the regeneration path are provided.

According to the said structure, when it becomes an overvoltage state at the time of energization direction switching, a regenerative path | route is formed and the backflow of the electric current to a power supply is suppressed, and each element can be protected from an overvoltage.
The driver circuit includes a bridge circuit including first and second driver circuit switching elements that are simultaneously turned on when the motor coil is driven, and the overvoltage detection circuit generates a detection signal for detecting an overvoltage. A switching element for detection and a switching element for the regenerative path, and the switching element for the regenerative path and a switching element for the low-side driver circuit among the switching elements for the first and second driver circuits. The regeneration pathway may be formed between the two.

According to this configuration, even when used for a small motor with a small mounting area, when an overvoltage state occurs when the energization direction is switched, the regeneration path is formed and the regeneration path is maintained until the regeneration current is sufficiently consumed. , The backflow of current to the power supply can be suppressed, and each element can be protected from overvoltage.
The driver circuit includes a bridge circuit including first and second driver circuit switching elements that are simultaneously turned on when the motor coil is driven, and the overvoltage detection circuit generates a detection signal for detecting an overvoltage. A switching element for detection, and a diode that is connected between the switching element for detection and the switching element for regenerative path and through which the detection signal flows, and the first, first, Among the two driver circuit switching elements, the driver circuit switching element on the low side may be turned ON, and the regeneration path may be formed by the driver circuit switching element on the low side.

According to this configuration, since the overvoltage detection circuit can be reduced in size, the single-phase brushless motor control device can be reduced in size.
The pre-driver may maintain the regeneration path for a necessary time based on the output of the driver circuit.
According to this configuration, the regenerative current can be reliably consumed even if the dead time is exceeded by maintaining the regenerative path for the necessary time.

The predriver includes an inverter with hysteresis for monitoring the output of the driver circuit, a latch circuit for holding data for a predetermined time based on the output and the output of the driver circuit, an output of the latch circuit, and an output of the rotor It is preferable to have an OR circuit that performs a logical sum with a signal whose position is detected.
According to this configuration, even when used in a small motor having a small mounting area, the regeneration path can be maintained for a desired time while reducing the size of the pre-driver.

  According to the present invention, an additional component such as a large-capacitance capacitor or a Zener diode, which causes an increase in cost, is not required, and an overvoltage state due to the disconnection of the regenerative current path can be suppressed. Destruction can be prevented.

1 is a block diagram of a single-phase brushless motor control device showing a preferred first embodiment of the present invention. FIG. FIG. 2 is a circuit diagram of a driver circuit and an overvoltage detection circuit shown in FIG. 1. FIG. 2 is a circuit diagram of the pre-driver shown in FIG. FIG. 4A is a timing chart for explaining the operation of the single-phase brushless motor control apparatus shown in FIG. 1, and FIG. 4B is an enlarged view of a portion A thereof. FIGS. 5A to 5C are schematic diagrams for explaining the operation (coil current path) of the single-phase brushless motor control device shown in FIG. It is a circuit diagram of a driver circuit and an overvoltage detection circuit showing a preferred second embodiment of the present invention. It is a block diagram of a general motor drive circuit. FIG. 8 is a timing chart for explaining the operation of the motor drive circuit shown in FIG. 7. FIG. 8 is a timing chart for explaining a PWM control operation of the motor drive circuit shown in FIG. 7. It is a block diagram of a conventional motor drive circuit. It is a timing chart for demonstrating operation | movement of the motor drive circuit shown in FIG. It is a block diagram of a general single phase motor drive circuit. FIG. 13 is a timing chart for explaining the operation of the single-phase motor drive circuit shown in FIG. 12. FIG. 13 is a circuit diagram of the pre-driver shown in FIG. 12.

Preferred embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of a single-phase brushless motor control device showing a preferred first embodiment of the present invention.
As shown in FIG. 1, the single-phase brushless motor control device 1 according to the first embodiment is used to control a single-phase brushless motor including a rotating rotor and a motor coil 13 wound around a stator. Is done.

This single-phase brushless motor control device 1 controls the direction in which the motor coil 13 is energized based on a rotor position detection signal S10 in which the position of the rotor is detected by a rotation sensor such as a hall element (not shown).
The single-phase brushless motor control device 1 includes a driver circuit (driver) 11 that controls energization of the motor coil 13 to drive the motor coil 13, a pre-driver 10 that generates a control signal that controls the driver circuit 11, and a driver. An overvoltage detection circuit 12 that detects an overvoltage state of the driver circuit 11 and forms a regeneration path (overvoltage protection circuit) when the potential of the output of the circuit 11 rises from a power supply voltage to a potential equal to or higher than a preset threshold; Is provided.

The driver circuit 11 includes driver circuit switching elements M11 to M14. As the switching element, a MOS transistor, bipolar transistor, FET, IGBT, or thyristor may be used.
The driver circuit 11 is composed of a bridge circuit including a total of four driver circuit switching elements M11 to M14 that are turned on simultaneously when the motor coil 13 is driven.

High-side and low-side upper and lower driver circuit switching elements M11 and M12 are connected to a line L1 connected to one output terminal OUT1 of the driver circuit 11, and are connected to the other output terminal OUT2 of the driver circuit 11. The driver circuit switching elements M13 and M14 of the upper and lower two stages of the high side and the low side are connected to the line L2.
The driver circuit switching elements M12 and M13 located on the diagonal line of the bridge circuit are one pair of switching elements, and the driver circuit switching elements M11 and M14 are the other pair of switching elements.

In the present embodiment, MOS transistors are used as the driver circuit switching elements M11 to M14. The p-channel MOS transistor is in the upper stage and the n-channel MOS transistor is in the lower stage.
The pre-driver 10 generates control signals for the driver circuit switching elements M11 to M14 based on the rotor position detection signal S10 and the outputs of the output terminals OUT1 and OUT2 of the driver circuit 11.

  When MOS transistors are used as switching elements, the pre-driver 10 generates GATE control signals P11, N11, P12, and N12, and performs switching control by opening and closing the gates of the MOS transistors. The driver circuit 11 controls energization to the motor coil 13 based on the GATE control signals P11, N11, P12, and N12 output from the pre-driver 10.

The overvoltage detection circuit 12 has one input terminal connected to the line L1 via the output terminal OUT1 of the driver circuit 11, and the other input terminal connected to the line L2 via the output terminal OUT2 of the driver circuit 11. The overvoltage detection circuit 12 is also connected to the input terminal of the pre-driver 10.
Here, the configuration of the overvoltage detection circuit 12 on the side connected to the other output terminal OUT2 of the driver circuit 11 will be described in more detail.

As shown in FIG. 2, the overvoltage detection circuit 12 is connected to the driver circuit 11 and the common power supply 14 and is controlled by a detection switching element M22 that generates a detection current Icrmp2 as a detection signal for detecting an overvoltage, and a detection current Icrmp2. And a regenerative path switching element M24.
A resistor R22 for converting the detection current Icrmp2 into current / voltage is connected to the drain of the detection switching element M22. Between the detection switching element M22 and the resistor 22, the gate of the regeneration path switching element M24 is connected. The output terminal OUT2 is connected between the source of the detection switching element M22 and the drain of the regeneration path switching element M24.

The configuration of the overvoltage detection circuit 12 on the side connected to one output terminal OUT1 of the driver circuit 11 is the same as described above. In this case, the detection signal is the detection current Icrmp1, and the resistor R21 is used instead of the resistor R22.
As shown in FIG. 3, the pre-driver 10 includes an inverter circuit 31 that generates an inverted signal of the rotor position detection signal S10, a dead time generation circuit 32 that generates a dead time of the rotor position detection signal S10 and the inverted signal, 33, extension circuits 34a and 34b for extending the dead times of the signals d1 and d3 of the dead time generation circuits 32 and 33 and the output terminals OUT1 and OUT2 of the driver circuit 11, and the outputs and dead of the extension circuits 34a and 34b. It comprises buffer circuits 34 to 37 connected to the outputs d1 to d4 of the time generation circuits 32 and 33, respectively.

The extension circuit 34a includes an inverter 35a with hysteresis that monitors the signal at the output terminal OUT1 of the driver circuit 11, a latch circuit 36a that selects data update or retention according to the monitoring result of the inverter 35a with hysteresis, and a latch circuit thereof. The OR circuit 37a calculates the logical sum of the output of 36a and the output of the dead time generating circuit 32.
A D-latch circuit is used for the latch circuit 36a. The output of the inverter 35a with hysteresis is connected to the G input of the D-latch circuit, the output d1 of the dead time generating circuit 32 is connected to the D input, and the OR circuit 37a is connected to the Q output. The extension circuit 34b has the same configuration as the extension circuit 34a.

  Based on the rotor position detection signal S10, the signal of the output terminal OUT1, and the signal of the output terminal OUT2, the pre-driver 10 outputs, as shown in FIG. 4A, the outputs IN1 and IN2 of the inverters with hysteresis 35a and 35b, and the dead time. The signals d1 and d3 from the generation circuits 32 and 33 and the signals dL1 and dL2 from the latch circuits 36a and 36b are generated. The signal level of the output IN2 of the inverter with hysteresis 35b instantaneously increases at time T4.

  Further, the pre-driver 10 uses these signals, OR circuits 37a and 37b, and buffer circuits 34 to 37 to control signals P11 and P12 of the switching elements M11 to M14 (dotted lines in P12 indicate the case of the conventional system), N11 , N12 and the energization control of the motor coil 13 by these control signals P11, P12, N11, N12.

Next, the operation of the single-phase brushless motor control device 1 will be described.
In FIG. 4, until the time T1, the motor is rotating forward as shown in FIG.
The pre-driver 10 turns on the driver circuit switching elements M11 and M14 and turns off the driver circuit switching elements M12 and M13 in order to pass the coil current Ia from the output terminal OUT1 to the output terminal OUT2.
From this state, at time T1, at the time of motor regeneration, which is the time of switching the energization direction of the coil current Ia, the pre-driver 10 turns off all the driver circuit switching elements M11 to M14.

Therefore, the current flowing in the motor coil 13 loses the regeneration path and tries to flow backward to the power source via the body diode of the driver circuit switching element M13. At this time, if the power supply device does not have a current sink capability, the power supply voltage VDD and the potential of the output terminal OUT2 rise.
Now, the potential of the output terminal OUT2 exceeds the threshold value Vth of the detection switching element M22 preset by the power supply. | OUT2-VDD | = | Vgs |> | Vth |
Then, as shown in FIG. 5B, since the detection switching element M22 is turned on, the detection current Icrmp2 flows toward the resistor R22.

The product of the current value of the detection current Icrmp2 and the resistance value of the resistor R22 exceeds the threshold value Vth. Icrmp2 × R22 = Vgs> Vth
Then, the regenerative path switching element M24 is turned ON, and a loop-shaped regenerative path C1 is formed between the low side regenerative path switching element M24, the ground, the driver circuit switching element M12, and the motor coil 13.

As described above, the pre-driver 10 determines whether the driver circuit 4 and the power supply circuit are in the overvoltage protection operation state using the threshold value Vth, and forms the regeneration path C1 to increase the potential of the power supply. Can be suppressed.
FIG. 5B shows a state between time T1 to time T2 and time T2 to time T4 in FIG. 4A, but the driver between the dead time Tdead that is between time T1 and time T2. The circuit switching elements M11 to M14 are OFF and serve as a body diode of the driver circuit switching element M12 as a regeneration path.

  In FIG. 4A, at the time T2 when the dead time Tdead has elapsed, the preamplifier 10 causes the output of the dead time generation circuits 32 and 33 to pass the coil current Ic from the output terminal OUT2 toward the output terminal OUT1. The driver circuit switching elements M13 and M12 are turned on, and the driver circuit switching elements M14 and M11 are turned off.

Here, as shown in FIG. 4A, when the regenerative current cannot be consumed within the dead time Tdead, that is, when the potential of the output terminal OUT2 is higher than the threshold value Vth, the hysteresis of the pre-driver 10 described in FIG. The output of the attached inverter 35b is a low level output, and the latch circuit 36b is in a data holding state.
Therefore, the control signal P12 input to the gate of the driver circuit switching element M13 remains a high level output that is a value before time T1, and the driver circuit switching element M13 maintains the OFF state, so that the necessary time is reached. Only the regeneration path C1 can be maintained.

In this way, by maintaining the regenerative path C1 for a necessary time, the regenerative current can be reliably consumed even if the dead time Tdead is exceeded.
FIG. 5B also shows the state at times T2 to T4 in FIG. 4, but the driver circuit switching element M12 is ON between times T2 and T4, and the regeneration path is for the driver circuit. It becomes the channel of the switching element itself.

In FIG. 4A, time T4 is the time when the regenerative current is sufficiently consumed and the overvoltage state ends.
When the regenerative current is consumed and the potential of the output terminal OUT2 becomes lower than the threshold value, the preamplifier 10 described in FIG. 3 causes the output of the inverter 35b with hysteresis to become a high level output, and the latch circuit 36b Become. Therefore, the output of the latch circuit 36b becomes the same low output as the output of the dead time generation circuit 32b.

Accordingly, the driver circuit switching element M13 is turned on, and a current flows through the motor coil 13 from the output terminal OUT2 side toward the output terminal OUT1 side as shown in FIG. 5C. As a result, the energization direction switching is completed, and the motor is in reverse rotation.
Thus, according to the single-phase brushless motor control device 1, as shown in FIGS. 4A and 4B, the potential of the output terminal OUT2 is set from the power supply voltage VDD between time T1 and time T4. It can be kept for a predetermined time while being in a slightly higher state.
Furthermore, since the single-phase brushless motor control device 1 instantaneously lowers the potential of the output terminal OUT2 at time T4, it is possible to prevent a sudden increase in the potential of the output terminal OUT2 as in the prior art.

As described above, even when the single-phase brushless motor control device 1 is used for a small motor having a small mounting area, when the overvoltage state occurs when the energization direction is switched, the regenerative path C1 is formed and the regenerative current does not flow. By maintaining the regeneration path C1, backflow of current to the power source can be suppressed and each element can be protected from overvoltage.
In the above description, the energization state from the output terminal OUT1 side to the output terminal OUT2 direction has been described using the energization switching from the output terminal OUT2 side to the output terminal OUT1 direction. The energization switching from the energized state toward the terminal OUT1 is also performed.

(Second Embodiment)
As shown in FIG. 6, the single-phase brushless motor control device 60 according to the second embodiment omits the regeneration path switching elements M23 and M24 of the overvoltage detection circuit 12 described in FIG. Are connected in series to the gates of the driver circuit switching elements M12 and M14 of the driver circuit 11, and between the drains of the detection switching elements 21 and 22, and between the driver circuit switching elements M12 and M14 and the resistors R21 and R22, The diodes D61 and D62 through which the detection current Icrmp2 flows are respectively connected.

  That is, the single-phase brushless motor control device 60 is not provided with a switching element that constitutes the driver circuit 11 and a switching element that constitutes the regenerative path separately as in the single-phase brushless motor control device 1 of FIG. By configuring the driver circuit 61 and the overvoltage detection circuit 62 as described above, the low-side driver circuit switching elements M12 and M14 constituting the driver circuit 61 are used for the drive / regeneration path.

In the single-phase brushless motor control device 60, when the potential of the output terminal OUT2 exceeds the threshold value Vth of the detection switching element M22 set in advance by the power supply, the detection switching element M22 is turned on, so that the detection current Icrmp2 is D62. Flows toward the resistor R22.
When the product of the current value of the detection current Icrmp2 and the resistance value of the resistor R22 exceeds the threshold value Vth, the driver circuit switching element M14 is turned on, and the driver circuit switching element M14 on the low side, ground, A loop-shaped regeneration path C6 is formed between the low-side driver circuit switching element M12 and the motor coil 13.

Other operations of the single-phase brushless motor control device 60 are the same as those of the single-phase brushless motor control device 1.
In this single-phase brushless motor control device 60, the same operation and effect as the single-phase brushless motor control device 1 can be obtained, and since the overvoltage detection circuit can be made smaller, the single-phase brushless motor control device 60 can be downsized. I can plan.

  The single-phase brushless motor control device described in the above embodiment is particularly useful when used for controlling a single-phase brushless motor provided in a relatively small acoustic device, video device, portable device, information device, or the like.

DESCRIPTION OF SYMBOLS 1 Single phase brushless motor control apparatus 10 Pre-driver 11 Driver circuit 12 Overvoltage detection circuit 13 Motor coil M11-M14 Switching element for driver circuits

Claims (5)

A single-phase brushless motor control device that controls the direction in which the motor coil is energized based on a signal that detects the position of the rotating rotor,
A driver circuit for driving the motor coil;
A pre-driver that generates a control signal for a switching element for a driver circuit that constitutes the driver circuit, based on a signal that detects the position of the rotor and an output of the driver circuit;
An overvoltage detection circuit that forms a regenerative path when the output potential of the driver circuit rises from a power supply voltage to a potential equal to or higher than a preset threshold;
A single-phase brushless motor control device comprising: a switching element for a regeneration path that constitutes the regeneration path. The driver circuit has a bridge circuit including first and second driver circuit switching elements that are simultaneously turned on when the motor coil is driven,
The overvoltage detection circuit includes a detection switching element that generates a detection signal for detecting an overvoltage, and the regeneration path switching element,
2. The single-phase brushless motor control according to claim 1, wherein the regeneration path is formed between the regeneration path switching element and a low-side driver circuit switching element among the first and second driver circuit switching elements. apparatus. The driver circuit has a bridge circuit including first and second driver circuit switching elements that are simultaneously turned on when the motor coil is driven,
The overvoltage detection circuit includes a detection switching element that generates a detection signal for detecting an overvoltage, and a diode that is connected between the detection switching element and the regeneration path switching element and through which the detection signal flows. Have
Of the first and second driver circuit switching elements, the low-side driver circuit switching element is turned ON by the detection signal flowing through the diode, and the regeneration path is formed by the low-side driver circuit switching element. The single-phase brushless motor control device according to claim 1.   The single-phase brushless motor control device according to claim 1, wherein the pre-driver maintains the regeneration path for a necessary time based on the output of the driver circuit.   The predriver includes an inverter with hysteresis for monitoring the output of the driver circuit, a latch circuit for holding data for a predetermined time based on the output and the output of the driver circuit, an output of the latch circuit, and an output of the rotor The single-phase brushless motor control device according to claim 4, further comprising an OR circuit that takes a logical sum with a signal that has detected a position.

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